System and Method for MIMO Split-Physical Layer Scheme for a Wireless Network

Abstract

A system employing split-PHY functionality across multiple access heads to establish multiple paths between a client device (CD) and an access network. Space-time coding includes transmitting one or multiple spatial streams through each access head. Macro transmit diversity includes transmitting a same signal, consisting of one or more spatial streams, from one or more access heads. A CD uses a strongest signal transmitted from at least one access head or diversity combining of two or more signals to recover the signal. Space-time coding includes receiving one or multiple spatial streams through each access head. Macro receive diversity includes receiving a same signal from a CD at one or more access heads. A strongest received signal is used to recover a signal or diversity combining of two or more signals received at different access heads is used to recover the transmitted signal.

1 - 20 . (canceled) 
     
     
         21 . A method for use in a multiple input multiple output (MIMO)-based wireless network, the method comprising:
 performing at least some physical (PHY) layer functionality in a centralized manner; and   performing at least some PHY layer functionality in a distributed manner, wherein the at least some PHY layer functionality that is performed in the distributed manner is (1) distinct from the at least some physical PHY layer functionality performed in the centralized manner, and (2) comprises performing analog modulation/demodulation.   
     
     
         22 . The method according to  claim 21 , wherein performing at least some PHY layer functionality in a centralized manner comprises at least one of:
 performing channel coding/decoding;   performing digital modulation/demodulation; and   performing constellation mapping/de-mapping.   
     
     
         23 . The method according to  claim 21 , further comprising:
 in a centralized manner, performing at least some media access control (MAC) layer functionality.   
     
     
         24 . The method according to  claim 21 , wherein performing at least some PHY layer functionality in a centralized manner comprises performing MIMO space-time coding/decoding. 
     
     
         25 . The method according to  claim 21 , further comprising, in a centralized manner, performing at least one of:
 scheduling of transmissions; and   selecting at least one technique from a set of techniques for processing a transmit/receive signal.   
     
     
         26 . The method according to  claim 21 , wherein performing analog modulation/demodulation comprises performing orthogonal frequency divisional modulation (OFDM) modulation/demodulation. 
     
     
         27 . The method according to  claim 21 , further comprising in the centralized manner, providing synchronization signals to control timing of wireless transmissions. 
     
     
         28 . The method according to  claim 21 , wherein performing at least some PHY layer functionality in the centralized manner comprises performing processing of a transmit signal according to at least one of the following techniques:
 a) macro-transmit diversity;   b) spatial reuse; and   c) spatial multiplexing.   
     
     
         29 . The method according to  claim 21 , wherein performing at least some PHY layer functionality in the centralized manner comprises performing processing of a receive signal according to at least one of the following techniques:
 a) macro-receive diversity;   b) spatial reuse; and   c) spatial multiplexing.   
     
     
         30 . The method according to  claim 21 , wherein performing at least some PHY layer functionality in the centralized manner is performed by a radio controller and performing at least some PHY layer functionality in a distributed manner is performed by a plurality of remote access heads, each remote access head having a coverage pattern, the method further comprising:
 providing an overall coverage pattern formed collectively by the coverage patterns of each of the plurality of remote access heads that is configured for one or more of:
 tailoring wireless coverage to a localized area provided by the plurality of remote access heads to a desired size and shape; 
 providing more uniform Signal and Interference and Noise Ratio (SINR) across a containment region; 
 minimizing undesirable signal leakage to areas outside of the containment region; and 
 dynamically selecting a subset of the plurality of remote access heads during each transmission/receive opportunity in order to minimize frame error rate and/or to maximize throughput. 
   
     
     
         31 . A multiple input multiple output (MIMO)-based wireless network system comprising at least one radio cluster, the radio cluster comprising:
 a radio controller configured to perform at least some physical (PHY) layer functionality in a centralized manner; and   a plurality of remote access heads configured to be connected to the radio controller and wherein each remote access head is configured to perform at least some PHY layer functionality distinct from that which the radio controller is configured to perform, the plurality of remote access heads collectively providing coverage to a localized area;   wherein the at least some PHY layer functionality performed by one or more of the plurality of remote access heads comprises analog modulation/demodulation.   
     
     
         32 . The system according to  claim 31 , wherein the at least some PHY layer functionality that the radio controller is configured to perform comprises at least channel coding/decoding or digital modulation/demodulation. 
     
     
         33 . The system according to  claim 31 , wherein the at least some PHY layer functionality that the radio controller is configured to perform comprises constellation mapping/de-mapping. 
     
     
         34 . The system according to  claim 31 , wherein the analog modulation/demodulation comprises orthogonal frequency divisional modulation (OFDM) modulation/demodulation. 
     
     
         35 . The system according to  claim 31 , wherein the radio controller communicates with the plurality of remote access heads using wired or unwired network links wherein:
 wired network link protocols include one or more of Ethernet, Infiniband, frame relay, and Asynchronous Transfer Mode (ATM); and   unwired network link protocols include one or more of IEEE 802.11, IEEE 802.16, Ultra Wide Band (UWB), and point-to-point microwave.   
     
     
         36 . The system according to  claim 31 , wherein the radio controller is configured to provide synchronization signals to the plurality of remote access heads to control the timing of wireless transmissions, and the at least some PHY layer functionality performed by the radio controller comprises MIMO space-time coding/decoding. 
     
     
         37 . The system according to  claim 31 , wherein for communications transmitted to or received from the plurality of remote access heads, the radio controller is configured to perform processing of a transmission or received signal according to at least one of the following techniques:
 a) macro-transmit diversity;   b) macro-receive diversity;   c) spatial reuse for one or both of a transmit signal and a receive signal;   d) spatial multiplexing for one or both of a transmit signal and a receive signal; and   e) some combination thereof.   
     
     
         38 . The system according to  claim 31 , wherein for a given radio cluster, each remote access head of the plurality of remote access heads is connected to the radio controller:
 directly via a point-to-point connection; or   indirectly via a fan-out arrangement through one or more other remote access heads.   
     
     
         39 . The system according to  claim 31 , wherein the at least one radio cluster operates as a single frequency network. 
     
     
         40 . The system according to  claim 31 , further comprising a network link between the radio controller and each of the plurality of remote access heads, the network link configured to provide one or more of:
 facilities to transmit packets between the radio controller and each remote access head of the plurality of remote access heads;   synchronization signals to be transmitted by the radio controller to each remote access head of the plurality of remote access heads; and   electrical power to be provided by the radio controller to at least one remote access head of the plurality of remote access heads.